Though I had been praying and waiting for a revival in my college it has not happened though I am retired five years after 23 years of service.
It was my teacher who taught English at the same seminary who inspired me to pray for the revival. She was a Canadian Mennonite missionary. The college was ready to move to a new campus about six hundred kilometers away in a few months. In one of the social gatherings in the seminary she revealed that the revival that she is praying for would happen before the move. It is 40 years since we moved to the new campus. But the revival she prayed for, and the one that I hoped for has not yet happened.

Why revival tarries? Is God ignoring prayers for revivals? No, because God is not against revivals. God desire his people to be spiritually alive. Holy Spirit, the spirit of newness is still at work as he did in the day of Pentecost.
History confirms that revivals happen only when the people are spiritually hungry and waiting for it. For example, take the pouring out of the Holy Spirit upon the 120 gathered in Jerusalem in the first century. Jesus had directed them “to wait for the promise of the Father” (Acts 1:4). So, they waited in one accord and devoted themselves to prayer in the upper room (Acts 1:14). Finally, when they were “altogether in one place” the Spirit poured out on them on the day of Pentecost (Acts 2:1-4).
This pattern of longing, waiting, and preparation in prayer is seen in all revivals. Sometimes God uses strange ways to prepare his people. For example, precursor for the Ao Naga revivals in India was the prophecy of a tribal chief long dead and gone. He had prophesied that some day in future a man with white skin will come and tell them about a new god. He told his people to wait for that person and follow his God. The people were waiting for the white man for years. They preserved the memory of this prophecy like a piece of charcoal soaked in fuel, ready to catch fire. It was set on flame and the fire covered the entire Ao Naga tribe when a white missionary strayed into their territory during the colonial period. Now 90% of Nagas are Christians. I know many such stories from Malaysia and other countries where God prepared his people to long for revivals.
In any revival there is a group of people earnestly waiting and praying for it. Prayer and longing had prepared them to receive it. Then in the process, the revival encompasses in its embrace everyone and even its critics sometimes. The first flame always fell upon an individual or a group who were ready for it. It is like a forest-fire beginning with an ember from the bonfire. It started small with a group of people longing for it and spread widely.
Revival never happens when people are not ready for it. But it happens when there is longing, waiting, and readiness.